In the days when I was an agent or produced election leaflets I discouraged the idea that we should rebut the claims of our opponents in the literature we put out.
My reasoning was that it was much better to concentrate on our own positive messages. If that wasn't enough then we were never going to win away.
Some support for this position comes from psychological research discussed in a 2007 Washington Post article - thanks to @sundersays for tweeting the link this morning.
The Post describes a study by the University of Michigan social psychologist Norbert Schwarz:
The federal Centers for Disease Control and Prevention recently issued a flier to combat myths about the flu vaccine. It recited various commonly held views and labeled them either "true" or "false." Among those identified as false were statements such as "The side effects are worse than the flu" and "Only older people need flu vaccine."
When ... Schwarz had volunteers read the CDC flier, however, he found that within 30 minutes, older people misremembered 28 percent of the false statements as true. Three days later, they remembered 40 percent of the myths as factual.
Younger people did better at first, but three days later they made as many errors as older people did after 30 minutes. Most troubling was that people of all ages now felt that the source of their false beliefs was the respected CDC.The same phenomenon, says the Post, has been observed in other experiments.
And Ruth Mayo, a cognitive social psychologist at Hebrew University in Jerusalem, has found that people tend to forget that someone was denying accusations over time - they just remember the association between him and the accusation:
"If someone says, 'I did not harass her,' I associate the idea of harassment with this person," said Mayo, explaining why people who are accused of something but are later proved innocent find their reputations remain tarnished. "Even if he is innocent, this is what is activated when I hear this person's name again.What do do?
Mayo found that rather than deny a false claim, it is better to make a completely new assertion that makes no reference to the original myth. Rather than say, as Sen. Mary Landrieu ... did during a marathon congressional debate, that "Saddam Hussein did not attack the United States; Osama bin Laden did," Mayo said it would be better to say something like, "Osama bin Laden was the only person responsible for the Sept. 11 attacks" - and not mention Hussein at all.It is not always easy to keep to this, but I am happy to publicise peer-reviewed science that chimes with my hunches or prejudices.